肋间神经冷冻止痛的实验及临床研究

目的 探讨减轻和消除开胸手术后剧烈胸痛的方法。方法 首先在－50℃条件下,分别以不同时间冷冻家犬肋间神经,观察病理改变及修复过程,寻找出可供临床应用的最佳冷冻时间。然后,按此冷冻时间,进行临床研究。对200例需开胸手术的患者随机分组,行冷冻止痛的前瞻性双盲对照研究。冷冻组与对照组各100例患者。冷冻组患者手术结束前常规冷冻切口、上下各一肋间以及放置引流管之肋间神经根部,根据视觉模拟评分法观察术后切口疼痛以及镇痛药使用情况;对照组患者除不用冷冻治疗外,其他处理同冷冻组。两组患者分别于术后第3,7,15,30,90天测定肺功能。结果 在家犬的实验中,随着冷冻时间的延长（30s-2.0min)神经轴索髓鞘的病理损害逐渐加重,但1个月后均恢复正常。能够有效止痛而且病理改变修复较快的冷冻时间是1.5min。将此冷冻时间用于临床研究。冷冻组止痛效果极为满意,VAS评分为2.29,对照组7.24,差异有非常显著性性意义（P＜0．001）;冷冻组疼痛0级22例（22％）,1－2级44例（44％）,3－4级20例（20％）5－6级8例（8％）,总有效率（0－6级）为94％;杜冷丁平均用量为41．3mg。对照组疼痛3－4级14例,5－6级20例,7－8级24例,9－10级42例,杜冷丁平均用量为41．3ng。对照组疼痛3－4级14例,5－6级20例,7－8级24例,9－10级42例,杜冷丁平均用量为185．0mg,2组差异有非常显著性意义（P＜0．001）。2组肺功能检测结果,差异无显著性意义。结论 冷冻肋间神经能够有效地预防开胸术后切口疼痛,此方法简便易行,而且神经的病理改变是可逆的。

Prospective double-blind randomized trial of cryoanalgesia: experimental and clinical study

OBJECTIVE: To alleviate and prevent postthoracotomy severe chest pain. METHODS: In dogs, intercostal nerves were freezed at -50 degrees C at different times. Pathological changes and repair process of the nerves were observed while identifying the best freezing time that could be used clinically. Prospective double-blind randomized trial in 200 patients who had undergone thoracotomy was carried out from January 1996 to June, 2000. Cryoanalgesia(Cryo group) and control group consisted of 100 patients. Before closing chest, 4 routes of costal nerves (incision, above and below incision, and one for inserting drainage tube) were freezed for 1.5 minutes separately. Postoperative incision pain was recorded by VAS(visual analogue scales) including recording the dosage of narcotics, pulmonary function on 3, 7, 15, 30, 90 postoperative days. RESULTS: Pathological changes of the axons and myelin sheaths progressed along with freezing time from 30 seconds to 2 minutes, but recovered in about one month. As the best freezing time, 1.5-minute freezing provided effective analgesia and quick recovery. Clinical application showed strong analgesia effect. VAS score of the cryo-group and control group was 2.29, and 7.24 (P < 0.001) respectively. In the cryo-group, no pain (0 degree) was observed in 22 patients (22%), very slight pain (1-2 degrees) in 44(44%), slight pain (3-4 degrees) in 20 (20%), and moderate pain (5-6 degrees) in 8 (8%). The total effective rate (0-6 degrees) was 94%. Dosage of dolantin in the cryo- and control groups was 41.3 mg and 185 mg, respectively(P < 0.001). The changes of pulmonary function for the two groups were not significant. CONCLUSION: Freezing intercostal nerves during thoracotomy can effectively prevent postoperative chest pain. The pathological changes of nerves are reversible.